Process for producing white or color resists on dyeings with vat dyestuffs on native or regenerated cellulose



United States Patent O" 3,097,045 PROCESS FOR PRODUCING WHITE R COLOR RESISTS 0N DYEIWGS WITH VAT DYESTUFFS ON NATIVE 0R REGENERATED CELLULOSE Hugo Bartl and Erich Feess, Frankfurt am Main, Germany, assignors to Farbwerke Hoechst Aktieugesellschaft vormals Meister Lucius & Briining, Franfiurt am Main, Germany, a corporation of Germany N0 Drawing. Filed Feb. 1, 1960, Ser. No. 5,665 Claims priority, application Germany Feb. 5, 1959 6 Claims. (Cl. 8-65) It is known that pads made on fabrics composed of native or regenerated cellulose with leucosulfuric acid esters of vat dyestuffs which contain such chemical agents as are conventionally used in the so-called chlorate steaming processes, namely an oxidation agent, an acid donator, and an oxygen carrier, can be resisted in white or in colors by overprinting them after drying with a printing paste containing in addition to alkali and a reducing agent if desired also vat dyestuifs. In general, the white and colored eifects produced in this manner are satisfactory. However, this process involves the disadvantage that the padded goods must be dried very carefully, lest the leucosulfuric acid ester should partly develop: into vat dyestufis and thus impair the purity of the effects. For this reason the padded goods are storable for a limited period only. In practice, the process is therefore considered as unsatisfactory.

It is further known that pads made with leucosulfuric acid esters of vat dyestuffs that contain sodium nitrite can be resisted in light shades by overprinting them with printing pastes which contain vat dyestuffs. In this process, the development to the vat dyestuff is eifected after ,the steamingby short action of hot dilute sulfuric acid.

At fuller shades, however, the white and colored resists are more or less dulled. Pads that contain chromate instead of nitrite exhibit the same disadvantage.

Even the first-print processes proved to be unsatisfactory, since one is compelled, after printing with the resist dyestuffs and steaming, to pad over the goods with the solution of leucosulfuric acid ester of vat dyestuffs and to develop them as soon as possible. This process does not allow of correcting the dyeings because the resist dyestuffs are printed first. In addition thereto, the compulsion of having immediately to treat the printed goods is incompatible with the desire to apply rational methods of operation, wherein, for example, it is endeavoured to collect several pieces of the same pattern for one bottom dyeing. Furthennore, at deeper shades the dyestuff take-up is affected because normally no steaming is carried out.

Now, We have found that pads that have been made on native or regenerated cellulose fabrics with leucosulfuric acid esters of anthraquinoid or indigoid vat dyestuffs with addition of the usual quantities of salts of nitrous acid, can be resisted in white and in colors, even in fuller shades. For this purpose there is printed on the pads dried at any desired temperature a printing paste which contains such a substance as is capable of destroying the nitrous acid prior to its acting on the leucosulfuric acid esters of the vat dyestuffs 'and,.in addition thereto, the

usual fixing agents and the chemical substance which is conventionally used as fixing auxiliary agent. If white resists are to be made, the printing paste may be applied at a pH ranging from 3-12. Preferably, it is applied at a pH of -8.

After drying, the prints are steamed in usual manner particularly in order to fix the vat dyestufi's. For developing the leucosulfuric acid esters of vat dyestufis, the

prints are treated for a short period with warm (about 30 to C.) dilute sulfuric acid of about 1-l0% 3,097,045 Patented July 9, 1963 ICC strength, and soaped in usual manner at the boil, rinsed and dried. When pure white resists are to be produced, the steaming may be dispensed with, but if it is applied, in most cases it is advantageous.

As salts of nitrous acid, there may be used all known stable salts of the nitrous acid; preferably and for economical reasons, one will use alkali metal and alkaline earth metal salts. The salts are generally applied at amounts of about 1 to about 30 g. per liter padding liquor. For better stability of the liquors and pads, the pH of the padding liquors of the leucosulfuric acid esters of vat dyestuffs is usually made weakly alkaline during preparation. The operation is generally carried out at a pH of about 7.5 to 12, preferably at 8.5 'to 10. For the adjustment of the pH value, there may be used in particular the carbonates, bicarbonates and the hydroxides of all alkali metals and alkaline earth metals that do not precipitate upon contact with sulfuric acid esters of leuco vat dyestuffs. In addition thereto, also organic bases that comply with the above requirement can be used. There are mentioned by way of example: mono-, diand tri-ethanolamin'e, dimethyl-aniline, or other, preferably aliphatic or aromatic amines of 10W molecular weight, further other basic compounds such as pyridine, etc.

In general, the salts of the nitrous acid are applied at such quantities that the concentration of the N0 ions in the padding liquors amounts to about '1 to 30 g./ 1., preferably 3 to 15 g./l.

As substances that are capable of destroying the nitrous acid, there may be used especially the compounds of the general formula wherein X represents hydrogen or a phenyl radical, and Y represents a primary amino group, a sulfonic acid group, a hydroxyl group, a-phenyl radical that may also be substituted by halogen atoms, amino or imino groups, oxalkyl radicals, sulfonic acid groups or carboxylic acid groups, further a carbonamide radical, a thiocarbonamide radical, an N-anilino radical that may also be substituted by sulfonic or carboxylic acid groups, and the benzoyl radical or the thiobenzoyl radical. In these compounds the carboxyl and sulfonic acid radicals may also carry amide or thioamide groups or they may be esterified with alcohols of low molecular weight, particularly with a lower alkanol. Furthermore, there may also be used the salts of the mentioned compounds with alkali metals or alkaline earth metals or with heavy metals preferably sodium or zinc, or with organic primary, secondary or tertiary bases, for example, aniline and trietlranolam-ine. The following compounds are mentioned by way of example:

Hydraziue, urea, thiourea, -hydroxylamine, diphenylamine, p-aminodiphenylamine, aniline and the halogen substitution products thereof such as 0-, m-, p-chloroand bromo-aniline, dichloroaniline, further, p-nitraniline, anisidine, phenylglycine, p-methoxyphenylgylcine, p-aminophenyl-glycine, which may also be used in the form of its soluble or insoluble salts with mineral or organic bases. It is also of advantage to use compounds that contain sulfonic acid or carboxylic acid groups, such. as sulfanilic acid, anthranilic acid, 3- or 4-aminobenzoic acid, 2- or 3- aminobenZene-sulfonic acid or the salts, esters, amides or thioamides thereof, for example, p-aminobenzenesulfamide or o-aminobenzenesulfonic acid methyl ester. Equally suitable are phenylhydrazine, phenylhydrazine-p-sulfonic or -carboxylic acid, p-phenylhydrazine-sulfonic acid- 3 methyl or -ethyl ester, and further benzoic acid amide and amidosulfonic acid and the esters thereof Anthranilic acid and phenylhydrazine-p-sulfonic acid proved to be particularly suitable. Apart from the chemical behaviour, the following points of View are important for the suitability of these compounds: the compounds must not volatilize during the drying of the printed goods and they must not be too easily water-soluble, because there will be caused unsharp outlines in both cases.

The quantity of the substance used for destroying the nitrous acid depends on the quantity of the nitrous acid applied and in particular on the capability of the leucosulfuric acid esters of the vat dyestulfs of being split off and oxidized. In general, there are applied quantities of about 10 to 200 g./kg. printing paste.

When in the preparation of white resists steaming is dispensed with, these requirements become less important so that there may be used substances which are easier soluble or volatile.

The take up of vat dyestuffs is not impaired by the compounds mentioned. On the contrary, some of them, especially the hydrazine and the phenyl-hydrazine distinctly fix vat dyestufis due to their reducing properties. According to the process of the present invention it is possible to produce white and colored resists not only on light ground shades, but also on medium and dark grounds. A further advantage of the process of the present invention is that the padding liquors and the padded goods can practically be stored for an unlimited period before further treatment, provided the action of light be prevented.

As tfixing agents, there may be used in the process of the present invention in particular the alkali metal, alkaline earth metal or zinc salts of the sulfoxylic acid, in the form of their addition compounds with lower aliphatic, aromatic or heterocyclic aldehydes. As aldehydes, there are preferably used aliphatic aldehydes having about 1-5 carbon atoms, and benzaldehyde and furfurol. Instead of the addition compounds mentioned, thio-urea dioxide may also be used as fixing agent.

The usual fixing auxiliary agents according to the present invention are, for example, glycerin, urea, triethanolamine, anthraquinone, etc.

The process of the present invention enables of producing surprisingly pure white and brilliant color resists; they can be prepared, in the ground as well as in the color efiects, in all shades of the color scale. The fastness properties of the articles so treated are equal in ground and color effects and correspond to those of vat dyestuffs.

The following examples illustrate the invention but they are not intended to limit it thereto:

Example 1 A cotton fabric is padded with a solution containing per litre G. Leucosulfuric acid ester salt of 2(4-chloronaphrthalene) 2' (4 methyl 5' chloro 7' methoxyindol)-indigo 20 Sodium nitrite 15 and Soda ash 3 The fabric is subsequently squeezed to 80% humidity and dried at 80 C.

The goods so prepared are then printed with a printing paste of the following composition:

Example 2 A fabric of staple fibre is padded with a solution containing per litre G. Leucosulfuric acid ester salt of 2-acenaphthene-2- thionaphtheneindigo 20 Sodium nitrite 5 and Soda ash 3 It is then squeezed to humidity and dried. The fabric so treated is subsequently printed with a printing paste of the following composition:

G. Dibenzopyrenquinone 20 Sodium formaldehydesulfoxylate 75 Soda ash 75 Phenylhydrazine-p-sulfonic acid 75 Starch-tragacanth thickening 00 and Water The fabric is then dried and steamed for 5-10 minutes. When developing in the manner described above, after having carried out an intermediate treatment with an oxidation agent such, for example, as hydrogen peroxide, sodium perborate or potassium bichromate, there are obtained pure yellow eifects on a red bottom.

Example 3 A fabric of viscose rayon is padded with a solution containing per litre:

G. Leucosulfuric acid ester salt of 4,4'-dimethyl-6,6'-dichlorothioindigo 20 Sodium nitrite 15 and Soda ash 3 squeezed to 80% humidity and dried. The fabric so treated is then printed with a printing paste of the following composition:

Phenylhydrazine 75 Crystal gum thickening 1:3 750 and Water After drying, the dyeing is developed in the manner described in Example 1. There are obtained White effects on a pink bottom. The resisting agent is volatile upon steaming, and an evenly dyed fabric is obtained by development.

If 75 g. of phenylglycine or p-methoxyaphenylglycine are used instead of phenylhydrazine, and if otherwise working in the same manner, there is obtained practically the same result.

Example 4 A fabric of cotton is padded with an aqueous solution that contains per litre:

The fabric is then squeezed and dried. The fabric so treated is then printed with a printing paste having the following composition:

Thiourea 100 Natural rubber 1:1 700 and Water 200 and, if desired after having intermediarily steamed, subsequently treated with hot, dilute sulfuric acid. There are obtained white eifects on blue bottom. Instead of 100 g. of thiourea, there may also be used in addition to 250 g. of urea 200' g. of amidosulfonic acid, in which case, however, the effects obtained are less pure.

Example A fabric of staple fibres is padded with a solution that contains per litre:

Leucosulfuric acid ester salt of the indigo Sodium nitrite 10 and Sodium carbonate 2 and subsequently dried. A printing paste of the following composition is printed on:

80 g. aniline, carefully dispersed in 700 :g. gum arabic 1:2 and 220 g. water padded with a solution containing per litre:

G. Leucosulfuric acid ester salt of thioindigo 10 Sodium nitrite 5 and Soda ash 10 After drying, the goods are printed with a printing paste consisting of:

Hydrazine hydrate 70 Gum arabic 1:1 700 and Water 230 After drying the fabric is treated as described in Example 5; there are obtained white resists on pink-colored bottom. Instead of hydrazine, there may also be used hydroxylamine.

We claim:

1. A process for producing White resists on pads that have been made on cellulose fabrics with leucosulfuric acidesters of vat dyestuffs selected from the group consisting of :anthraquinoid and indigoid vat dyestuffs, with the addition of salts of nitrous acid, which comprises overprinting the dried pads with a printing paste essentially consisting of a fixing agent and 120% by weight of a substance that destroys nitrous acid and has the general formula wherein X represents a member selected from the group consisting of the phenyl radical and the hydrogen atom, and Y represents a member selected tfirom the group consisting of the -NH radical, a sult'om'c acid group, a sultonic acid amide group, a sulfonic acid thioamide group, a sulfonic acid radical esterified by a lower alcohol, an OH radical, a phenyl radical, a substituted phenyl radical, a carbonamide group, a thiocarbonamiide group, an N- anilino radical, an N-anilino radical substituted by a sulfonic acid group, an N-anilino radical substituted by a sulfonic acid group esterified by a lower alcohol, an N- anilino radical substituted by a carboxylic acid group, an N-anilino radical substituted by a carboxylic acid group esterified by a lower alcohol, at least one of X and Y represents an aromatic radical, the benzoyl radical, the thiobenzoyl radical and salts of the said compounds, steaming and treating the pads with dilute sulfuric acid at a temperature of 30-90 C., soaping, rinsing and drying the fabric so treated.

2. A process as claimed in claim 1 wherein the substance that destroys the nitrous acid and that is contained in the printing paste is phenylhydrazine p-sulfonic acid.

3. A process as claimed in claim 1 wherein the substance that destroys the nitrous acid and that is contained in the printing paste is anthranilic acid.

4. A process for producing color resists on pads that have been made on cellulose fabrics with leucosulfuric acid esters of vat dyestuffs selected from the group consisting of anthraquinoid and indigoid vat dyestuffs, with the addition of salts of nitrous acid, which comprises overprinting the dried pads with a printing paste, essentially consisting of a fixing agent, a vat dyestufl and 1-20% by weight of a substance that destroys nitrous acid and has the general formula wherein X represents a member selected from the group consisting of the phenyl radical and the hydrogen atom, and Y represents a member selected from the group consisting of the -NH radical, a sul-fonic acid group, a sulfonic acid amide group, a sulfonic acid thioamide group, a sultonic acid radical esterified by a lower alcolhol, an OH radical, a phenyl radical, a substituted phenyl radical, a oarbonamide group, a thiocarbonamide group, an N-anilino radical, an N-B.Dll1ll10 radical substituted by a sulfonic acid group, an N-anilino radical substituted by a sulfonic acid group esterified by a lower alcohol, an N- anilino radical substituted by a carboxylic acid group, an 'N-anil ino radical substituted by a carboxylic acid group ester-ified by a lower alcohol, at least one of X and Y represents an aromatic radical, the benzoyl radical, the thio'benzoyl radical and salts of the said compounds, steaming and treating the pads with dilute sulfuric acid at a temperature of 3090 C., soaping, rinsing and drying the fabric so treated.

5. A process as claimed in claim 4 wherein the substance that destroys the nitrous acid and that is'contained in the printing paste is anthranilic acid.

6. A .pnocess as claimed in claim 4 wherein the substance that destroys the nitrous acid and that is contained in the printing paste is phenylhydrazine p-snlfonic acid.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain 1903 OTHER REFERENCES Diserens, The Chemical Technology of Dyeing and Printing, vol. 1, 1948, Reinhold Pub. Co., New York, pp. 193, 198, 199.

Knecht and Fothergill, The Principles and Practice of Textile Printing, 4th ed., 1952, Grifiin & Co. Ltd., London, England, pp. 717, 814-815, 818. 

1. A PROCESS FOR PRODICING WHITE RESISTS ON PADS THAT HAVE BEEN MADE ON CELLULOSE FABRICS WITH LEUCOSULFURIC ACID ESTERS OF VAT DYESTUFFS SELECTED FROM THE GROUP CONSISTING OF ANTHRAQUINOID AND INDIGOID VAT DYESTUFFS, WITH THE ADDITION OF SALTS OF NITROUS ACID, WHICH COMPRISES OVERPRINTING THE DRIED PADS WITH A PRINTING PASTE ESSENTIALLY CONSISTING OF A FIXING AGENT AND 1-20% BY WEIGHT OF A SUBSTANCE THAT DESTROYS NITROUS ACID AND HAS THE GENERAL FORMULA 